Experimental demonstration of in-service dispersion monitoring in 960km WDM transmission system using optical frequency-modulation method

We demonstrate the in-service dispersion monitor in a 16 * 10.6 Gb/s 960-km wavelength-division-multiplexing transmission system. We use the optical frequency method for the dispersion monitor, and modify it so as to be able to detect the sign of the dispersion without the loss of simplicity. The accuracy of the dispersion monitoring and the influence on the bit-error-rate performance are experimentally evaluated.